Data analysis for SEM-EDX, thermokinetics, surfactant, and corrosion inhibition activity of Co(II) and Zn(II) complexes of pyrrole-based surfactant ligand

This manuscript reports a dataset for the scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), surfactant properties, thermokinetics, and corrosion inhibition activity of [[Co(HL)2.2H2O] Cl2.H2O]] (1) and [[Zn(HL)2.Cl] Cl.3H2O]] (2) complexes with surfactant-based Schiff base ligand (HL). It contains analyzed data related to thermokinetics, such as the activation energy (E*), entropy change (∆S*), enthalpy change (∆H*), and free energy change (∆G*) of HL and metal complexes. It also contains the SEM micrographs and EDX images of the studied ligand and metal complexes. A detailed analysis of the critical micelle concentration (CMC) data and figures illustrating the surfactant behavior of the synthesized complexes are presented in this article. The data for the corrosion inhibition activity of all synthesized compounds are also included. The dataset is related to the research article entitled “Bioinorganic interest on Co(II) and Zn(II) complexes of pyrrole-based surfactant ligand: Synthesis, characterization, and in silico-ADME study”.

Materials science Specific subject area Analytical Chemistry, Corrosion, and surface science Type of data Tables, Images, and Figures How the data were acquired Thermogravimetric analysis: Perkin Elmer STA60 0 0 thermal analyzer under the N 2 atmosphere. The slopes and intercepts of thermogravimetric analysis and differential thermal analysis (TGA/DTA) plots were analyzed to obtain thermokinetics data. A JEOL 6390 LA scanning electron microscope was used to generate SEM micrographs of the ligand and complexes and EDX images of complexes. Conductivity: An Auto Ranging digital conductivity TDS meter TCM 15 + was used to record conductivity data at 308 and 318 K temperatures. Corrosion inhibition: The weight loss method was used to evaluate corrosion inhibition on carbon steel coupons using a four-digit digital balance (Sartorius QUINTIX 224-1S analytical balance). Data format Raw and analyzed data Description of data collection Using Origin software, thermokinetic parameters were generated from TGA/DTA data. The conductivity data were processed in easy plot software to calculate CMC and Gibb's free energy of micellization. The SEM-EDX imaging was performed to analyze surface morphology and elemental composition. Corrosion inhibition data on carbon steel coupons were used to measure anticorrosion efficacy. Data

Value of the Data
• Researchers in the area of material science may find the present data useful in investigating kinetic behavior and surfactant properties of compounds used in drug delivery systems. • The SEM-EDX images are helpful in identifying morphological changes that occur during complexation of the ligand for the formation of metal complexes. • Corrosion inhibition efficiency data collected for carbon steel (CS) coupons can be used to evaluate the efficacy of the inhibitor in other corrosive solutions (media). • This result can be used to compare the thermal stability and decomposition rates of other surfactant-fabricated metal complexes.

Objective
The surface properties of the metal complexes make them particularly suitable for pharmaceutical applications. Several factors influence biochemical interactions with pathogens, includ-  ing adsorption ability, thermokinetic stability, and surface morphology. The main goal of this study is to explore the data on how they selectively bind to specific regions of the pathogens by forming micellar aggregates at different temperatures based on degrees of micellization and free energy of micellization. The surface morphology and grain size of the complexes determine drug delivery effectiveness. Their anti-corrosion properties also make them ideal for a wide range of metal-based components as well as pharmaceutical applications. The datasets included in this manuscript are additional quantitative parameters that will add significant value to the complexes and support our previous publications [ 1 , 2 ].

Data Description
In this study, we share SEM-EDX, thermokinetics, CMC, free energy of micellization, and anticorrosion activity data for [ ( 2 ) complexes with surfactant-based Schiff base ligand ( HL ) ( Fig 1 ). The ligand was prepared by refluxing of a mixture of an ethanolic solution of pyrrole-3-carbaldehyde ( P3C ) and laurylamine ( LA ) in a 1:1 stoichiometric ratio.
The SEM micrographs of ligand and complexes are presented in Fig. 2 . The micrographs illustrate the variation in surface morphology for metal complexation of ligands with metal ions. The somewhat rod-shaped crystalline structure of the micrograph of HL has changed to the unevenly distributed morphological mass of the complexes after complexation. Table 1 reports the elemental composition of the complexes detected from EDX analysis. It revealed the presence of various non-metal atoms, such as N, O, and Cl, and the respective metals. The EDX data indicated the expected elemental composition of the complexes as well, and the EDX images are shown in Mendeley Research data file [3] .
The Coats-Redfern equation was used to calculate the thermodynamic and kinetic parameters of each decomposition step for the synthesized complexes. The results are presented in Table 2 . A consecutive increase in the E * value in each decomposition step was observed. Table 2 showed negative S * , positive H * , and positive G * values for all complexes [4][5][6] . Details regarding these parameters can be found in Section 3.2 .
The conductivity versus concentration plots of LA , complex 1 and complex 2 are shown in Figs. 3-5 . The specific conductivity values varied before and after CMC. Owing to the formation

Table 2
Thermodynamic and kinetic parameters.

Complexes
Step Here, r is Pearson's correlation coefficient, and A is Arrhenius pre-exponential factor. Here S1and S2 represent premicellar and postmicellar slopes. of micelles with lower ionic mobility, the conductivity decreases after the CMC point [7] . Table 3 presents physicochemical data calculated from conductivity vs concentration plots. A higher CMC was reported for LA and complexes 1 and 2 at 318 K than at 308 K. A larger CMC value for LA (1.5 × 10 -2 M) compared to complex 1 (3.21 × 10 −4 M) and complex 2 (1.98 × 10 −4 M) was also reported previously [1] . The Gibbs free energy of micellization ( G o m ) was negative for all ( Table 3 ) and became more negative from LA to complex 1 and then to complex 2 at a particular temperature, indicating spontaneity. The anticorrosion activity was investigated using the weight-loss method, and the corrosion parameters are listed in Table 4 . Table 5 presents the mass loss data for the carbon steel coupons during the experiments. Graphs showing the corrosion rate, inhibition efficiency, and surface coverage are shown in Figs. 6-8 .

Thermogravimetric Analysis
TGA/DTA analysis was performed in Perkin Elmer STA60 0 0 thermal analyzer with vertical type furnace under N 2 atmosphere. The heating scan of the sample was done from 40 to 750 °C at a linear heating rate of 10 °C/min. The data were processed in Origin software to extract thermokinetics parameters. The parameters such as E * , H * , S * , and G * of each decomposi- Where α is the fraction decomposed at time t, β denotes the linear heating rate, A denotes the Arrhenius pre-exponential factor, and R represents the general gas constant. A plot of the   left-hand side against 10 0 0/T of equation (1) gives a straight line whose slope (-E * /R ) determines the activation energy (kJmol −1 ), and the intercept indicates the value of A in the s −1 unit. Using equations (2, 3, and 4), other thermodynamic parameters such as the G * , H * , and S * were determined [6] . In equation (2), k B is Boltzmann constant and h is Plank's constant.

Surfactant Activity Study
Conductivity measurements were performed to investigate the surfactant properties of the synthesized complexes. The study was conducted at temperatures of 308, and 318 K. The CMC was determined by plotting the specific conductivity ( κ) against the concentration of the surfactant solution. The intersection of the two lines defines the CMC point, from which the degree of micellization ( α) was calculated using the formula: α = S 2 /S 1 (5) Similarly, Gibb's free energy of micellization was calculated from the formula:

Corrosion Inhibition Activity Study
Carbon steel (CS) coupons cut to sizes of 2 cm × 2 cm × 0.07 cm were abraded with 80, 320, 60 0, 80 0, 10 0 0, and 120 0 grade emery (silicon carbide) papers. Stock solutions (10 0 0 ppm) of HL , complex 1 , and complex 2 inhibitors were prepared in 100 mL of a 1.0 N HCl solution. The stock solution was diluted to obtain solutions with the desired concentrations of 80 0, 60 0, 40 0, and 200 ppm. Distilled water-washed, acetone-dried, and moisture-free abraded coupons were weighed and immersed in 25 mL of diluted solutions in crucibles with and without inhibitors. After 6 h of exposure, the coupons were removed and weighed as described above. Measurements were performed in triplicate to reduce errors. The size of each coupon was measured by using a digital screw gauge. The corrosion rate (CR) (mm/yr), inhibition efficiency (IE) percent ( η), and surface coverage ( θ ) were calculated using the following equations (7-9) [9] .
Where w represents the weight loss in grams, d is the density of the CS in grams per cc, A is the area of the CS coupons, and t represents immersion time in hours.
Here, CR and CR' denote the corrosion rates in the absence and presence of the inhibitors, respectively.
Surface coverage , θ = Where, w 1 and w 2 represent the weight reduction in the absence and presence of the inhibitor, respectively.

Declaration of Competing Interest
The authors declare no competing financial interests or personal relationships that could influence the study reported in this article.

Ethics Statements
This study did not involve human or animal subjects or social media platforms for analysis. Therefore, data ethics statements were not required based on the journal policy.